1. Field of the Invention
This invention relates to a surface-stabilized ferroelectric liquid crystal (SSFLC) element in a bistable orientation state. The SSFLC has applications as for a display, a printer head and the like.
2. Description of the Prior Art
N. A. Clark et al. have disclosed (for example, in U.S. Pat. No. 4,367,924 and U.S. Pat. No. 4,563,059) that a liquid crystal element is bistable, i.e., which produces two different stable orientation states in the absence of an electric field, and so, has a memory capability as a result, can be obtained by disposing a ferroelectric smectic (chiral smectic C or H) liquid crystal (which produces a sprial alignment structure in bulk) between a substrate spacing small enough for supporessing a spiral alignment structure thereof. N. A. Clark et al. use the application of magnetic field or shearing to obtain the bistable orientation state, but practically speaking, it is preferable to use rubbing processing or oblique evaporation processing for orientation processing. A liquid crystal element in which rubbing processing or oblique evaporation processing has been utilized in order to obtain a bistable orientation state having a monodomain has been disclosed, for example, by S. Okada et al. in U.S. Pat. No. 4,639,089. However, a ferroelectric smectic liquid crystal having a bistable orientation state with a monodomain obtained by rubbing processing or oblique evaporation processing has a disadvantage in that the amount of transmission light under the memory state is smaller compared with the bistable crystal of N. A. Clark et al.
Accordingly, the present inventor has investigated the possibility of producing a novel bistable orientation state which attains the same degree of optical modulation effect product from a bistable orientation state as that disclosed by N. A. Clark et al., even while utilizing the more practical rubbing processing or oblique evaporation processing as the orientation processing means.